Evidence continues to accumulate on the multifactor etiology of bronchial asthma, as well as on the numerous precipitants of asthmatic attacks within the same individual. Several recent studies have consistently demonstrated that physical exercise is a predominant trigger of asthmatic attacks in a large group of asthmatics. The sophistication of treatment for this component of asthma does not, however, match the refinement offered by the research findings on etiology. The present study is designed to assess the effectiveness of conditioned bronchial dilation as a treatment for exercise induced asthmatic attacks. The conditioning procedure will involve the instigation of bronchial constriction through physical exercise followed by reward for increased bronchial dilation (assisted initially with bronchodilators.) The training will be undertaken with two groups of asthmatic children who are known to respond to exercise with bronchoconstriction.